1. Field of the Invention
The present invention relates to endovascular devices for occluding and/or stabilizing and sealing off vasculature or body passageways, tissue defects, and aneurysms. More specifically, the present invention relates to a method and apparatus for threading wires into body cavities and detaching end sections thereof using vibrational energy, for example, in the form of elastic waves.
2. State of the Art
A variety of methods have been developed for occluding and/or stabilizing and sealing off vasculature or body passageways, tissue defects and aneurysms with the use of endovascular catheters including injectable particles, injectable glue, and detachable coils and other devices. The use of detachable coils appears to be gaining widest acceptance for aneurysm therapy, perhaps because of the ease and precision of control of the delivery and disposition of the coil at the desired occlusion site.
One approach for delivering and detaching coils at an occlusion site involves forming or attaching the coil at the distal end of a wire, and then threading the coil and wire through a catheter until the coil is disposed at the occlusion site. An electric current is then applied to the proximal end of the wire and conducted through the wire to the point of origin or attachment of the coil where it causes the coil, for example, by electrolysis, to detach from the wire. See U.S. Pat. Nos. 5,569,245, 5,624,449, 5,122,136, 5,540,680, and 5,354,295.
Among the problems associated with the electrically detachable coil approach is the time necessary to effectuate detachment (which changes with increasing number of devices delivered), the lack of reliability that the coil will detach, discomfort with the use of a grounding needle (insertable in the flesh of the patient) required for the proper functioning of the device, generation of particulates from the detachment site (electrolysis), and inability to select the size of the coil in vivo.
It is therefore an object of the invention to provide an apparatus and method for selectively detaching an end section of a wire in a body passageway by non-electrical means.
It is another object of the invention to provide such an apparatus and method in which the end section of the wire may be quickly and reliably detached, independently of the number of devices delivered.
It is a further object of the invention to provide such an apparatus and method in which little discomfort results to the patient.
It is still another object of the invention to provide such an apparatus and method, in accordance with one aspect thereof, in which multiple sections of the end segment of the wire may each be selectively detached at different times.
It is an additional object of the invention to provide such an apparatus and method, in accordance with another aspect thereof, in which it may readily be determined by the user when the end section of the wire has detached.
It is a further object of the invention to provide such an apparatus and method in which little preparation of the wire and end section is required to allow for subsequent use and detachment of the end segment.
It is still another object of the invention to provide such an apparatus and method in which therapeutic fluid may be delivered along with the wire to a target body location.
The above and other objects of the invention are realized in a specific illustrative embodiment of a wire apparatus with a detachable distal end which includes an elongate wire (either solid or hollow) having a distal end section, and a discontinuity located rearwardly of the distal end section for rupturing when vibrational energy is applied thereto. The apparatus includes a delivery means coupled to the elongate wire for delivering therapeutic fluid to a target body location and a vibrational energy generator, preferably an ultrasound generator, for applying vibrational energy to the wire to travel to the discontinuity to cause detachment of the distal end section. The vibrational energy may comprise axial or torsional waves mechanically induced into the wire.
In use, the wire is threaded through a vasculature or body passageway to a target location, and therapeutic fluid is injected through a catheter or hollow wire to the target location. Then vibrational energy is applied to the wire to cause the distal end section to detach and remain at the target location to occlude the passageway, and the remainder of the wire is withdrawn from the patient.
In accordance with one aspect of the invention, the discontinuity could include a cut in the wire, a hole, a reduced diameter section, an abrupt increase in mass, an adhesive, soldered or spot-welded joint which joins the distal end section to the wire, a coil soldered or adhesively attached to either the outer surface of a solid or hollow wire, or to the inner surface of a hollow wire, or a heat or chemically treated section. Alternatively, the distal end section could include a plurality of discontinuities, each adapted to rupture at a different vibrational levels or frequencies, to detach a selected portion of the distal end section which is distal to the discontinuity being ruptured.
Other objects, features and advantages of the invention will become apparent from a consideration of the following detailed description presented in connection with the accompanying drawings